org.kynosarges.tektosyne.subdivision

Class PolygonGridMap

java.lang.Object

org.kynosarges.tektosyne.subdivision.PolygonGridMap

All Implemented Interfaces:

SubdivisionMap<PointI>

public final class PolygonGridMap
extends java.lang.Object
implements SubdivisionMap<PointI>

Maps the faces of a planar Subdivision to PolygonGrid locations. Provides a mapping between all faces of a planar Subdivision and the PointI locations of the PolygonGrid from which the Subdivision was created.

The mapping is realized by a pair of arrays for optimal runtime efficiency. However, PolygonGridMap will not reflect changes to the underlying Subdivision or PolygonGrid.

Constructor Summary

Constructors

Constructor and Description
PolygonGridMap(PolygonGrid grid, PointD offset, double epsilon) Creates a PolygonGridMap from a new Subdivision to the specified PolygonGrid.

Method Summary

Modifier and Type	Method and Description
PointI	fromFace(SubdivisionFace face) Converts the specified SubdivisionFace into the associated PointI location.
Subdivision	source() Gets the Subdivision that contains all mapped Subdivision.faces().
PolygonGrid	target() Gets the PolygonGrid that defines all mapped PointI locations.
SubdivisionFace	toFace(PointI value) Converts the specified PointI location into the associated SubdivisionFace.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PolygonGridMap

public PolygonGridMap(PolygonGrid grid,
                      PointD offset,
                      double epsilon)

Creates a PolygonGridMap from a new Subdivision to the specified PolygonGrid. Sets target() to grid, and source() to a new Subdivision that contains all mapped Subdivision.faces() created from grid locations. All Subdivision coordinates are based on PolygonGrid.gridToWorld(int, int).

offset may be null which is interpreted as PointD.EMPTY. Otherwise, the Subdivision.faces() of the new Subdivision are shifted by offset.

epsilon may be equal to or less than zero, in which case one millionth of the RegularPolygon.length of the current PolygonGrid.element() is used. We cannot use exact coordinate comparisons because shared vertices of adjacent grid elements are unlikely to evaluate to the exact same coordinates in all cases.

Parameters:

grid - the PolygonGrid that defines all mapped PointI locations

offset - an optional offset by which to shift grid

epsilon - the maximum absolute difference at which coordinates should be considered equal

Throws:

java.lang.NullPointerException - if grid is null

Method Detail

source

public Subdivision source()

Gets the Subdivision that contains all mapped Subdivision.faces().

Specified by:

source in interface SubdivisionMap<PointI>

Returns:

the Subdivision that contains all Subdivision.faces() accepted and returned by fromFace(org.kynosarges.tektosyne.subdivision.SubdivisionFace) and toFace(org.kynosarges.tektosyne.geometry.PointI), respectively

target

public PolygonGrid target()

Gets the PolygonGrid that defines all mapped PointI locations.

Specified by:

target in interface SubdivisionMap<PointI>

Returns:

the PolygonGrid that defines all PointI locations returned and accepted by fromFace(org.kynosarges.tektosyne.subdivision.SubdivisionFace) and toFace(org.kynosarges.tektosyne.geometry.PointI), respectively

fromFace

public PointI fromFace(SubdivisionFace face)

Converts the specified SubdivisionFace into the associated PointI location.

Specified by:

fromFace in interface SubdivisionMap<PointI>

Parameters:

face - the SubdivisionFace to convert

Returns:

the PointI location associated with face

Throws:

java.lang.IllegalArgumentException - if source() does not contain face, or face is the unbounded SubdivisionFace

java.lang.NullPointerException - if face is null

toFace

public SubdivisionFace toFace(PointI value)

Converts the specified PointI location into the associated SubdivisionFace.

Specified by:

toFace in interface SubdivisionMap<PointI>

Parameters:

value - the PointI location to convert

Returns:

the SubdivisionFace associated with value

Throws:

java.lang.IllegalArgumentException - if value does not map to any SubdivisionFace within source()